KR20130110314A - Hydraulic unit and electronic control brake system for automobile having it - Google Patents

Abstract

PURPOSE: A modulator block and a vehicular brake system applied with the same are provided to move a pad backwards from a disc, thereby effectively preventing a residual frictional force generated from a contact between the disc and the pad. CONSTITUTION: A vehicular brake system includes an electronic control unit, a master cylinder, a wheel brake, multiple normal open (NO) type solenoid valves (11) and normal close (NC) type solenoid valves (12), a low-pressure accumulator (14), a pump (13), a motor (15), a NO type shuttle valve (16), a traction control (TC) solenoid valve (17), and a residual frictional force control unit (20). The master cylinder generates hydraulic brake pressure according to the actuation of a brake pedal. The NO type solenoid valves and the NC type solenoid valves control the flow of the hydraulic brake pressure. The low-pressure accumulator temporarily stores a fluid from the wheel brake when the electronic control unit implements an anti-lock brake system (ABS) mode through the NO type solenoid valves and the NC type solenoid valves. The pump and the motor pressurize the fluid in the low-pressure accumulator, and discharge the fluid to the wheel brake or the master cylinder. For a traction control system (TSC) mode, the NC type shuttle valve is placed on an oil suction flow path which is connected from the master cylinder to the inlet of the pump. The TC solenoid valve is placed between the master cylinder and the outlet of the pump, and the residual frictional force control unit is placed between the TC solenoid valve and the outlet of the pump. The electronic control unit moves the fluid in the wheel brake to the residual frictional force control unit in order to move a pad backwards from a disc.

Description

Modulator block and vehicle brake system employing the same {Hydraulic Unit and Electronic control brake system for automobile having it}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a brake system for a modulator block vehicle, and more particularly to an electronically controlled brake system for a vehicle that prevents residual friction forces that occur between a disk and a pad.

Generally, a vehicle includes a plurality of wheel brakes including a caliper device having a disk and a pair of pads for braking front and rear wheels for deceleration or stoppage while the vehicle is running, and a booster And a master cylinder are mounted. When the driver depresses the brake pedal, the hydraulic pressure formed in the booster and the master cylinder is transmitted to the pad of the wheel brake, and the pad presses the disk to generate the braking force. However, when the driver presses the brake pedal to control the increase or maintenance of the braking force, if the braking pressure is greater than the road surface state or the friction force of the wheel brake generated by the braking pressure is greater than the braking force generated from the tire or the road surface, the tire is removed from the road surface. Sliding slippage occurs.

Recently, the anti-lock brake system (ABS), which prevents the sliding of the wheel during braking, prevents the slip phenomenon from being effectively applied to provide a strong and stable braking force and to make driving easier. Traction Control System (TCS), which prevents excessive slip of the wheel during rapid start or acceleration, and the anti-lock brake system when the vehicle is not adjusted to the driver's will by external force during high speed driving of the vehicle. A brake system having an electronic stability control system (ESC: Electronic Stability Control System or VDC: Vehicle Dynamic Control System) is being developed to maintain a stable driving state by controlling the brake by combining traction control.

As described above, various conventional vehicle brake systems for controlling hydraulically actuated parts and modulator blocks equipped with a plurality of solenoid valves, accumulators, motors and pumps, and the like are used to control braking hydraulic pressure transmitted to the wheel brake side. It includes the electronic control unit (ECU) in common. The electronic control unit senses the vehicle speed through each wheel sensor disposed on the front wheel and the rear wheel, thereby controlling the operation of each solenoid valve, the motor, and the pump.

However, in the conventional vehicle brake system, a pair of pads for pressing the disk of the wheel brake and the disk from both sides may contact with each other finely while driving without causing braking pressure due to uneven wear or the like. Contact between the disk and the pad generates residual friction, which causes acceleration and running loss.

Embodiments of the present invention allow the pad to be spaced apart from the disk to suppress residual frictional forces caused by contact between the pad and the disk.

According to an aspect of the present invention, the braking of the master cylinder, the master cylinder to form a braking hydraulic pressure in accordance with the operation of the brake control pedal, the electronic control device, the brake pedal to enable antilock brake mode (ABS mode) and traction control mode (TCS mode) control Wheel brakes including a caliper device for advancing a disk provided in a vehicle and a pair of pads for pressurizing the disk to receive the wheel braking force by receiving the hydraulic pressure, respectively provided upstream and downstream of the brake brake A plurality of NO type solenoid valves and NC type solenoid valves for controlling the pressure, the low pressure accumulator for temporarily storing the fluid discharged from the wheel brake side during ABS mode braking, and pressurizing the fluid stored in the low pressure accumulator to discharge to the wheel brake side or the master cylinder side Pump and motor, between the low pressure accumulator and the pump Is an on-vehicle brake system including a check valve, an NC-type shuttle valve provided on an oil inlet flow path connected from the master cylinder to the inlet side of the pump for TCS mode, and a TC solenoid valve provided between the outlet side of the pump and the master cylinder. In this case, the electronic control apparatus may provide a vehicle brake system for moving the fluid in the closed circuit section provided on the wheel brake side to the hydraulic control apparatus so as to retract the pad from the disk.

In addition, the residual friction force control unit may include an electronic control valve and an actuator.

In addition, the electronic control device is a closed circuit provided by closing the TC solenoid valve and opening the electronic control valve to provide a closed circuit section (L1-1), the NO-type solenoid valve on the wheel brake side is opened and the NC-type solenoid valve is closed. In communication with the section, the fluid in the closed loop section (L1-2) can be moved to the residual frictional force control unit.

According to another aspect of the present invention, a plurality of NO solenoid valves and NC type solenoid valves respectively provided on the upstream side and the downstream side of the wheel brake to control the flow of the braking hydraulic pressure, and from the wheel brake side when the ABS mode braking of the solenoid valve A low pressure accumulator in which the discharged fluid is temporarily stored, a pump and a motor for pressurizing the fluid stored in the low pressure accumulator to be discharged to the wheel brake side or the master cylinder side, and an oil suction passage connected to the inlet side of the pump for the TCS mode. An NC-type shuttle valve, a TC solenoid valve provided on the outlet side of the pump, and a modulator block provided between the outlet side of the pump and the TC solenoid valve and including a residual friction control unit including an electronic control valve and an actuator can be provided. Can be.

In addition, the closed circuit section (L1-1) formed by closing the TC solenoid valve and the electronic control valve is opened, and the closed circuit section (L1) formed by opening the NO-type solenoid valve on the wheel brake side and closing the NC-type solenoid valve. -2), the actuator may move the fluid in the closed loop section (L1-2) to the residual frictional force control unit through the closed loop section (L1-1) in communication.

According to an embodiment of the present invention, the fluid in the closed circuit section, which is formed by closing a section of the wheel brake side hydraulic circuit among the entire hydraulic circuits of the brake system, is moved out of the closed circuit section using the residual friction control module, thereby increasing the volume of the fluid on the wheel brake side. By reducing the pressure, the pad can be retracted from the disk to effectively prevent the residual friction generated when the disk and the pad contact each other.

1 is a view schematically showing a vehicle brake system according to an embodiment of the present invention.
2 is a view illustrating a hydraulic circuit diagram and a closed circuit section provided in a modulator block of a vehicle brake system according to an exemplary embodiment of the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a view schematically showing a vehicle brake system used in an embodiment of the present invention. Referring to the drawings, an electronically controlled brake system for a vehicle includes a brake pedal (1), a booster (2) for amplifying and outputting the pedal effort of the brake pedal (1), and a master for converting the pressure amplified from the booster (2) into hydraulic pressure. And a modulator block (6) connected to the cylinder (3), the master cylinder (3), and the hydraulic pipe (4) to transfer and control the braking hydraulic pressure to each wheel brake (5). The wheel brake 5 includes a caliper device including a disk mounted on the wheel, a pad located on both sides of the disk, and a piston for moving the cylinder back and forth to press the pad by the braking hydraulic pressure .

2 is a view showing a hydraulic circuit diagram provided in the modulator block of the vehicle brake system according to the present embodiment. In this embodiment, a vehicle stance control system capable of controlling an anti-lock brake system (ABS) and a traction control system (TCS) Control: ESC) as an example.

Typically, the master cylinder 3 is provided with two ports consisting of a primary port and a secondary port for respectively controlling two wheel brakes FR, FL, RR and RL, respectively, Each of which has a hydraulic circuit. Since the configuration of the secondary hydraulic circuit 10B is substantially the same as the configuration of the primary hydraulic circuit 10A, the primary hydraulic circuit 10A will be mainly described below, and a repetitive description of the secondary hydraulic circuit will be omitted. However, the pump 13 and the pump (not shown) provided in each hydraulic circuit are driven together with a phase difference of 180 degrees by one motor 15. [

As shown in FIG. 2, the primary hydraulic circuit 10A provided in the modulator block 6 includes a plurality of solenoid valves for controlling braking hydraulic pressure delivered to two wheel brakes 5 (RL, FR). (11, 12), the pump 13 for sucking and pumping fluid from the fluid (oil) or the master cylinder 3 exiting the wheel brake side 5, and the fluid exiting the wheel brake 5 temporarily. A low pressure accumulator 14 for storage and an oil suction passage which guides the fluid of the master cylinder 3 to be sucked into the inlet side of the pump 13 in the TCS mode.

A plurality of solenoid valves (11, 12) are connected to the upstream side and the downstream side of the wheel brake (5). A solenoid valve 11 disposed on the upstream side of each wheel brake 5 is a solenoid valve 11 of NO (normally open) type which is kept open in a normal state and a solenoid valve 12 disposed on the downstream side And is an NC (normally closed) type solenoid valve 12 that is maintained in a normally closed state. The opening and closing operations of the solenoid valves 11 and 12 are respectively controlled by an electronic control unit (ECU) (not shown) that senses the vehicle speed through a wheel sensor (not shown) disposed on each wheel side. Type solenoid valve 11 is closed and the NC type solenoid valve 12 is opened so that the fluid that has escaped from the wheel brake 5 side is temporarily stored in the low pressure accumulator 14. [

The pump 13 is driven by the motor 15 to suck and discharge the fluid stored in the low pressure accumulator 14 to transfer the hydraulic pressure to the wheel brake 5 side or the master cylinder 3 side.

An NC type electric shuttle valve 16, which allows the fluid to flow only to the inlet side of the pump 13, is provided in the middle of the oil suction path for guiding the fluid of the master cylinder 3 to be sucked to the inlet side of the pump 13, An NC type shuttle valve (ESV) is installed. The shuttle valve 26 is normally closed and opened in the TCS mode.

An NO-type solenoid valve 17 (hereinafter, referred to as a TC solenoid valve) for controlling the TCS mode is provided in the main flow path connecting the primary port of the master cylinder 3 and the outlet side of the pump 13. The TC solenoid valve 17 maintains the normally opened state so that the brake fluid pressure formed in the master cylinder 3 during normal braking through the brake pedal 1 is transmitted to the wheel brake 5 side through the main flow path, In the mode control, the electronic control unit performs the closing operation. Although not shown, a relief passage and a relief valve are provided between the oil suction passage and the main passage. The relief flow path and the relief valve return the braking hydraulic pressure discharged from the pump 13 in the TCS mode to more than necessary to return it to the master cylinder 3 side.

In addition, an electromagnetic control valve 21 and an actuator 22 are provided as the residual frictional force control unit 20 between the pump 13 of the main flow path and the TC solenoid valve 17. The electronic control valve 21 is provided in an NC type so as not to operate during normal braking, and the actuator 22 uses a diaphragm actuator. The diaphragm actuator 22 is operated by two solenoid valves 23 and 24. The solenoid valve 23 is connected to the vacuum booster 25 so that the diaphragm actuator 22 has a vacuum suction force, and the solenoid valve 24 is connected to the atmosphere so that the diaphragm actuator has a toe output.

Hereinafter, the operation of the vehicle brake system according to the present embodiment having the above-described structure will be described.

If a slip occurs during braking in a vehicle equipped with this brake system, the electronic controller performs ABS mode by mixing into three modes, such as depressurization, boosting and maintaining pressure, based on signals input from each wheel sensor. Each control mode of the ABS is not controlled to all four wheels (FR, FL, RR, RL) in the same state, but can be controlled separately according to the road condition and the ABS control state. Each control mode will be described step by step through the primary hydraulic circuit 10A.

First, when the braking force is exerted by the hydraulic pressure generated in the master cylinder 3 by depressing the brake pedal 1 by the user, the braking pressure on the wheel brake 5 associated with the primary hydraulic circuit 10A is changed to the road surface condition The solenoid valve 11 is closed and the NC type solenoid valve 12 is opened to perform the ABS depressurization mode so as to lower the pressure to the appropriate pressure (depressurization mode). Then, the hydraulic pressure (fluid) partially escapes from the wheel brake 5 side and temporarily stored in the low-pressure accumulator 14, so that the braking pressure of the wheel brake 5 mounted on each wheel is lowered to prevent the slip of the road surface.

The electronic control unit drives the motor 15 to increase the hydraulic pressure of the wheel brake 5 so that the pump 13 of the primary hydraulic circuit 10A is operated to increase the hydraulic pressure of the wheel brake 5. [ The ABS pressure increasing mode is performed. That is, the fluid stored in the low-pressure accumulator 14 is pressurized through the pump 13 and is transmitted to the wheel brake 5 side through the open-type NO-type solenoid valve 11, thereby increasing the braking pressure. At this time, the hydraulic pressure discharged from the pump of the secondary hydraulic circuit is returned to the master cylinder in accordance with the braking pressure condition or transmitted to the wheel brake side associated with the secondary hydraulic circuit.

When the braking pressure reaches a state in which the optimum braking force is generated or the braking pressure needs to be kept constant to prevent resonance of the vehicle, the electronic controller performs the ABS pressure holding mode. The ABS pressure holding mode eliminates the pressure change in the wheel brake 5, thereby closing the NO-type solenoid valve 11 of the primary hydraulic circuit 10A to block the hydraulic pressure from moving. At this time, the hydraulic pressure discharged from the pump 13 is transmitted to the master cylinder 3 side, whereby the ABS pressure holding mode is stably performed.

On the other hand, the TCS mode is performed when the electronic control unit senses a slip phenomenon that occurs when the user depresses the accelerator pedal (not shown) in a slippery condition on the road surface, and then the slip phenomenon occurs. In the TCS mode, the NC type shuttle valve 16 of the oil suction path is opened, the TC solenoid valve 17 of the main flow path is closed, and the motor 15 and the pump 13 are operated to pump the fluid .

That is, when the TCS mode is performed, the fluid on the master cylinder 3 is sucked into the inlet of the pump 13 through the oil suction passage, and the fluid discharged to the outlet of the pump 13 flows through the NO- Is transmitted to the wheel brake (5) via the brake (11) and acts as a braking pressure. As a result, when the driver presses the accelerator pedal for rapid start, the wheel is locked even if the brake pedal 1 is not pressed, so that the vehicle starts slowly and stably even under a slip condition where the road surface is not good.

Meanwhile, in the constant speed mode such as a cruise mode, the electronic control device has a residual friction prevention mode (Active Brake mode) in which the distance between the disk and the pad is adjusted so that residual friction generated when the disk and the pad are in non- -pad Retraction System (ABRS, hereinafter referred to as ABRS mode). That is, in the ABRS mode, the electronic control device moves a part of the fluid in the hydraulic circuit on the wheel brake 5 side, thereby reducing the hydraulic pressure of the piston which presses the pad, thereby causing the pad to retract from the disk.

Specifically, when the ABRS mode is performed, the electronic control unit first closes the TC solenoid valve 17, and the electronic control valve 21 of the residual friction control unit 20 is opened to close the closed circuit section L1- at the outlet side of the pump. 1) (see the thick line on the top of the drawing). The closed loop section L1-1 communicates with the closed loop section L1-2 formed on the wheel brake side when the NO type solenoid valve 11 and the NC type solenoid valve 12 are in a normal state (the lower side of the figure is thicker). Line).

When the solenoid valve 23 is operated, the actuator 22 is driven to operate the incompressible fluid in the closed circuit section L1-1 and the closed circuit section L1-2, in particular, the fluid in the closed circuit section L1-2 on the wheel brake 5 side. Is moved to the residual frictional force control unit 20 through the open electronic control valve 21. As a result, the fluid volume in the closed circuit section L1-2 on the wheel brake side is reduced so that the piston is retracted and the pad is spaced away from the disk.

On the other hand, when the solenoid valve 24 operates, the fluid in the residual frictional force control unit 20 is returned to the closed circuit section L1-2 on the wheel brake side by atmospheric pressure, thereby enabling normal braking operation.

1..Brake Pedal 2..Booster
3. Master cylinder 5. Wheel brake
6. Modulator block 10 A. Primary hydraulic circuit
10B .. Secondary hydraulic circuit 11 ... NO solenoid valve
12 .. NC type solenoid valve 13 .. pump
14 .. Low Pressure Accumulator 15 .. Motor
16..NC type shuttle valve 17..NO type TC solenoid valve
18. Check valve 20. Residual friction control unit
21.NC type solenoid valve 22 .. Actuator
23,24 solenoid valve

Claims (5)

A master cylinder 3 which forms a braking hydraulic pressure in accordance with the operation of the brake pedal 1 and a master cylinder 3 which forms a braking hydraulic pressure in accordance with the operation of the brake pedal 1, And a caliper device for advancing and retracting a pair of pads for pressing the disc. The wheel brake 5 is provided on the upstream side of the wheel brake 5 Type solenoid valve 11 and an NC-type solenoid valve 12 provided on the downstream side of the solenoid valves 11 and 12 for controlling the flow of the braking oil pressure, A pump 13 and a motor 15 for pressurizing the fluid stored in the low pressure accumulator 14 and discharging the fluid to the wheel brake side or the master cylinder side, NC mode shuttle valve 16 provided on the oil suction flow path connected from the master cylinder 3 to the inlet side of the pump 13 for the mode, and between the outlet side of the pump 13 and the master cylinder 3 In a brake system for a vehicle comprising a TC solenoid valve 17, and a residual friction control unit 20 provided between the outlet side of the pump 13 and the TC solenoid valve 17,
The electronic control device is a vehicle brake system for moving the fluid on the wheel brake side to the residual friction force control unit (20) to retract the pad from the disk. The method of claim 1,
The residual friction control unit (20) is a brake system for a vehicle comprising an electronic control valve (21) and an actuator (22). The method of claim 2,
The electronic control device is a TC solenoid valve 17 is closed, the electronic control valve 21 is opened to provide a closed circuit section (L1-1), the NO brake type solenoid valve 11 on the wheel brake side is open NC type The solenoid valve 12 is in communication with the closed loop section (L1-2) provided to close, the vehicle brake system for moving the fluid in the closed circuit section (L1-2) to the residual frictional force control unit (20). ABS mode of the plurality of NO solenoid valves 11 and NC solenoid valves 12 and solenoid valves 11 and 12 provided on the upstream side and the downstream side of the wheel brake 5 to control the flow of braking hydraulic pressure, respectively. A low pressure accumulator 14 in which fluid discharged from the wheel brake side is temporarily stored during braking, a pump 13 and a motor 15 for pressurizing the fluid stored in the low pressure accumulator 14 to discharge the fluid to the wheel brake side or the master cylinder side; , The NC-type shuttle valve 16 provided on the oil suction passage connected to the inlet side of the pump 13 for the TCS mode, the TC solenoid valve 17 provided on the outlet side of the pump 13, and the pump ( A modulator block provided between the outlet side of 13) and the TC solenoid valve 17 and including a residual friction control unit 20 including an electronic control valve 21 and an actuator 22. 5. The method of claim 4,
The TC solenoid valve 17 is closed and the solenoid valve L1-1 is formed by opening the electronic control valve 21, and the NO type solenoid valve 11 on the wheel brake side is opened and the NC solenoid valve ( 12) communicates the closed loop section (L1-2) formed by closing,
The actuator (22) is a modulator block for moving the fluid in the closed loop section (L1-2) to the residual frictional force control unit (20) through a closed loop section (L1-1) in communication.

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